The present invention relates to a magnetic recording head for use in a magnetic recording drive, and the magnetic recording drive using the same, and in particular, to a perpendicular magnetic recording head that can be driven even at a high frequency, and a small-sized and large-capacity perpendicular magnetic recording drive enabled to operate by using the same.
A magnetic recording drive is provided with a medium for magnetically recording information, a magnetic recording head for writing information to, or reading information from the medium, a write-read operation control circuit for reproducing information on the basis of output signals from the magnetic recording head, and recording information on the basis of signals inputted, a mechanism for rotating or shifting the medium, and a positioning mechanism for determining the position of the magnetic recording head, relative to the medium. On the surface of the medium, there are included regions for recording information, regions for recording servo data for positioning of the magnetic recording head, and linkage regions disposed between those regions. Since no information is recorded in the linkage regions, it is required that the regions for recording information be expanded by setting up the linking regions as small as possible to thereby enhance the capacity of the hard-disk drive.
In order to promote advances in the hard-disk drive towards larger capacity and miniaturization, it has been proposed that for the medium, use is made of a perpendicular magnetic recording medium having a recording layer made of a hard magnetic material that can be easily magnetized in the perpendicular direction against a substrate. It is effective for recording information at higher density in such a perpendicular medium to provide a soft underlayer between the recording layer and the substrate. That is because the soft underlayer provided enables a recording field produced by the magnetic recording head to be enhanced, and read output to be enhanced.
The magnetic recording head comprises a write element for producing the recording field to record information in the medium, and a read element for reproducing signals written on the medium. FIG. 1 shows a section of the magnetic recording head by way of example. An underlayer 11 made of alumina, and so forth, on the order of 1 μm in thickness, is disposed on a substrate 1 made of Al2O3-TiC, and over the underlayer 11, there is disposed a read element 2 formed by sequentially depositing a lower shield layer 21 made of Ni80Fe20, and so forth, on the order of 1 μm in thickness, a magnetoresistive sensor 20, and an upper shield layer 22 made of Ni80Fe20, and so forth, on the order of 1 μm in thickness. Further, a write element 3 is deposited on the read element 2 with a spacer 12 made of alumina, and so forth, on the order of 0.25 μm in thickness, interposed therebetween.
The write element 3 is formed by depositing a return pole 33 made of Ni80Fe20, and so forth, on the order of 2 μm in thickness, coils 35 (parts thereof not shown in the figure) made of Cu, and so forth, on the order of 2 μm in thickness, an auxiliary pole 31 made of Ni80Fe20, and so forth, on the order of 1.5 μm in thickness, and a main pole 30 made of Fe70Co30, and so forth, on the order of 0.2 μm in thickness, in that order. Magnetic fluxes generated by causing a current to flow to the coli 35 are converged by use of a yoke 32 and the auxiliary pole 31 to be guided to the main pole 30. Using magnetic fluxes passing through the tip of the main pole 30, information is written to a medium (not shown in the figure). Magnetic fluxes passing through the medium are fed back to the main pole 30 through the return pole 33.
FIG. 2 is a perspective view showing the write element 3. The coils 35 are not shown in the figure. The auxiliary pole 31 is in a plane shape tapered towards an air bearing surface 4 to cause magnetic fluxes to efficiently converge on the main pole 30. Further, as disclosed in, for example, JP-A No. 36503/2003, because the auxiliary pole 31 is disposed so as to be deposited on the underside of the main pole 30, and further, is recessed from the air bearing surface 4, magnetic fluxes leaking from the auxiliary pole 31 have no adverse effect on recording.
In JP-A No. 101612/2001, it is disclosed that an auxiliary magnetic pole, a main pole, and a return pole are preferably disposed in that order from the side of a substrate for recording information sharply.